Analysis Of The Mechanical Performance And Its Influence Factors Of Large Blast Furnace Shell Taphole

The blast furnace taphole locates in the blast furnace hearth, this region faces much more gas and hot metal pressure than other regions, meanwhile, it also has to bear the impact of taping machine, and sometimes, it has to work under high temperature if the brick lining near the taphole is broken. The study on the blast furnace taphole is similar to the problem of pressure vessel with holes. Although the problem of pressure vessel with holes is widely studied by many researchers at home and abroad, the special study on the blast furnace is very rare, especially on the mechanical performance and its influence factors of large blast furnace taphole. In this paper, Systematical analysis of the mechanical performance and its influence factors of large blast furnace taphole with the volume of 4800m3 is taken by the finite element software ANSYS11.0 and some meaningful conclusions are obtained.The research theory in this paper is combination of elastic stress analysis and plastic criteria, which is very suitable for the structural model of blast furnace taphole with partial plastic in whole elastic.The process including modeling, choosing element, meshing, loading and constraining with the software ANSYS, is Systematically introduced in this paper, meanwhile, a size range of finite element mesh of the blast furnace taphole is obtained.A detailed elastic analysis of the taphole and its surrounding area are carried out, and though it, the biggest stress around the taphole and its location are found and the security of the taphole is evaluated with the theory of stress concentration. Then, elastoplastic limit analysis of the model is taken and the distribution law of plastic area, deformation properties around the taphole and the limit load of the structure are accessed.Because the blast furnace taphole has the possibility of working under high temperature, the contrastive analysis of the taphole in different temperature is taken from the angle that high temperature may cause of declining in the yield strength and elastic modulus of the material, the contrastive analysis includes stress, deformation, plastic area and the limit load, through the analysis, we find that the plastic area, strain and deformation of the taphole under higher tempertature are far greater than the situation under room temperature, while the limit load of structure under higher temperature also declines to a certain degree. Nevertheless, the structure under the temperature of 250OC still has a certain capacity and isn't destroyed immediately. Moreover, the time of the taphole working under high temperature is generally short, so the structure model is safe under the accidental high temperature.In order to improve the mechanical performance of the blast furnace taphole, the stiffener of the taphole is generally used. In this paper, the influence of the stiffener on the mechanical performance of the taphole is systematically studied. Several models are built according to the length, location and thickness of the stiffener, and then, elastic and elastoplastic analysis are carried out on the models. The results of the analysis prove that the longer the stiffeners is, the effect of restriction on the high nominal elastic stress is more obvious, moreover, the stiffeners setted on both sides is superior to the ones setted on single side. The thickness of the stiffener's increasing in a certain range can also decline the high nominal elastic stress and plastic area around the taphole obviously, but the influence will be weakened if the thickness exceed a certain range, both the length and thickness of the stiffener can effectively restrict the development of the plastic area and the influence of thickness is more obvious in terms of restricting the deformation of the taphole. Both the thickness and length increasing can improve the limit capacity of the structure, especially increasing the thickness of the taphole is very effective on improving the ductility of the structure.In this paper, a large number of holes on the furnace shaft are not built during the modeling process and these holes would weaken the stiffness of the structure if they are built. In order to find out whether the weakening of the upper stiffness impact the mechanical performance of the taphole and the simplified approach is reasonable in this paper, two models with different stiffness of upper structure are built, and elastic and plastic analysis are carried out, from the results of the analysis we find that the simplified approach in this paper is suitable for elastic and elastoplastic analysis under one times standard load, but not suitable for limit analysis, therefore, the limit load obtained in this paper is not true limit load of the structure, nevertheless, the analysis of the factors that influence limit load is still very helpful.